The very long term goal of this project is to determine the structure of the bacterial ribosome at atomic resolution. The goal of just our laboratory over the next six to eight years is to determine the structures of several of those proteins whose functions are best understood and which seem most important. During the two years of requested support (1/Jan/74-31/Dec/75) we plan to grow and to characterize crystals of some five or ten ribosomal proteins. I plan to return from Uppsala, Sweden with some 100 to 200 mg each of the 21 proteins from the small subunit and with luck some crystals. Our proposed work includes (1) purifying more protein from supplied 30S and 50S subunits (2) exploring crystallization conditions for the various proteins and (3) attaching heavy atom derivatives to crystallized proteins. Once we have obtained usable heavy atom derivatives, we plan to request additional research support for the actual structure determination(s).